Loudspeaker enclosure

ABSTRACT

Enclosure and mounting for a loudspeaker is combined with enclosure and mounting for an ionization sensor, a printed circuit board and a battery. The battery and portions of the front portion and rear portion of the device intersect with the other portions in such fashion that no fasteners such as screws, rivets, adhesive or the like are utilized to retain these portions in assembled relation.

United States Patent Wieder July 1,1975

[ 54 l LOUDSPEAKER ENCLOSURE [76] Inventor: Horst K. Wieder, i207 Riverview Ln., Watertown, Wis. 53094 22 Filed: July 2, 1974 21 Appl. No: 485,120

Related US. Application Data [63] Continuation-impart of Ser. No. 377,76l, July 9,

1973, Pat. No. 3,835,256.

[52] US. Cl 179/179; 340/237 S [51] Int. Cl. G08B 17/12 [58] Field of Search l79/l E, 179; 312/7 R,

3l2/DlG. l7; 325/l I9, 352, 353, 355, 356; IMO/228.1, 237 S [56] References Cited UNITED STATES PATENTS 3,594,751 7/197! Ogden et al. 340/228 Primary Examiner-Kathleen H. Claffy Assistant E.mminerGeorge G. Stellar Attorney, Agent, or Firmlohn M, Diehl [57] ABSTRACT Enclosure and mounting for a loudspeaker is combined with enclosure and mounting for an ionization sensor, a printed circuit board and a battery. The battery and portions of the front portion and rear portion of the device intersect with the other portions in such fashion that no fasteners such as screws, rivets, adhesive or the like are utilized to retain these portions in assembled relation.

1] Claims, 9 Drawing Figures LOUDSPEAKER ENCLOSURE CROSS-REFERENCES This application is a continuation-in-part of my copending application Ser. No. 377.76l filed July 9.

1973. having the same title now US. Pat. No. 3.835.256.

FIELD This invention relates to a loudspeaker enclosure and more particularly to a combination enclosure for a loudspeaker and other components.

PRIOR ART The device of the invention is particularly adapted to serve as a heat detector and smoke detector which provides an audible alarm signal in response to tempera ture rise or ionization of the ambient atmosphere which exceeds preselected limits.

Many devices fitting this general description have been marketed and many others have been proposed.

However. the combination of mechanical features which characterize the device disclosed herein is believed to be heretofore unknown.

The present device is believed to be. from a mechanical point of view. essentially a loudspeaker enclosure wherein other components. notably a printed circuit board. an ionization sensor and a battery. have been combined within the same enclosure.

No similar relationship between a speaker and a printed circuit board or a speaker and a battery is believed to have been heretofore proposed.

Likewise. no such device is believed to have been proposed heretofore wherein the use of fasteners such as screws has been so limited.

SUMMARY Combination speaker and printed circuit board asembly is provided as in the above-referenced application of which this application is a continuation-in-part application. As in the disclosure therein. the assembly comprises a minimum of parts other than the speaker itself. the printed circuit board with such components as an ionization sensor and a testing switch mounted thereon. the associated wiring and in this instance. a battery; the number of such other parts in that case was three and in this case four. Two of these parts together with the printed circuit board are assembled with screws and then the remaining parts. which are made slightly resilient. are snapped together.

The device which is thus provided may be assembled with great economy and may also be installed with case. thereby with little labor and thereby also with economy.

The device may be operated off 110V. AC line current or off a self-contained battery or offa remote battery or may be operated off l lOv. AC line current with either a self-contained battery or remote battery on automatic standby to provide continued functioning in the event of interruption of line current.

It may be attached either to a plain wall surface or to a standard electrical outlet box depending on the source of power to be used.

The device may operate other alarm devices in addi tion to the one contained within the device.

For locations in such places as homes. it may be installed to provide easy removability from the wall and easy disassembly. both without tools. for any desired purpose. such as to change a battery.

For locations in such places as motels. it may be made tamper-proof" to anyone unwilling to use a screwdriver simply by installing four screws.

If line current is relied upon as a power source. a light emitting diode may be provided to indicate continued operation of the device.

If power is obtained solely from the battery which may be provided within the device. means is provided to test the batterys functioning from time to time.

OBJECTS It is an object of the invention to provide an improved speaker enclosure.

Another object is to provide an improved combination enclosure for printed circuit board and loudspeaker.

Another object is to provide such a device as an alarm device of the type usually referred to as a smoke detector.

Another object is to provide such a device which may be both manufactured and installed with great economy.

Another object is such a device which may be assembled with a minimal number of fasteners.

Further objects will become apparent from the drawings and from the following detailed description.

DRAWINGS In the drawings like reference numerals refer to like parts and:

FIG. I is a plan view from the top or front of the device of the invention;

FIG. 2 is a partially cut-away plan view of the embodiment of FIG. I with the grill and guard portion removed;

FIG. 3 is a fragmentary cross-sectional view taken on lines 3-3 in FIG. 2;

FlG. 4 is a fragmentary cross-sectional view taken on lines 44 in FIG. 1;

FIG. 5 is a plan view from the back, bottom or rear of the device:

FIG. 6 is a cross-sectional view taken on lines 66 in FIG. 1 showing the attachment of one embodiment of the invention to a standard electrical outlet box;

FIG. 7 is a fragmentary cross-sectional view taken on lines 77 in FIG. 2 with the base portion omitted;

FIG. 8 is a fragmentary enlarged portion of the plan view of FIG. 2; and

FIG. 9 is a schematic view showing operation of part of the device.

DESCRIPTION Alarm devices which respond to heat and smoke to indicate the presence or potential presence of fire have traditionally been relatively expensive and some have been relatively unreliable. In accordance with the objects. the present invention provides a relatively cconomical relatively reliable such alarm device.

Referring now to the figures. the enclosure of the invention comprises resiliently deformable guard portion 10. speaker bracket portion II having leg portions 12, loud speaker 13 comprising diaphragm l4 and cup 15, printed circuit board 16 having ionization sensor 17 and test switch 18 mounted thereon, base portion 19 and rear bracket portion 20.

Grill and guard portion I is provided with a plurality of apertures in its face which provide a grill and are dis posed in front of the loudspeaker system to facilitate outward travel of sound waves emitted by the diaphragm of the loudspeaker. A certain number of these apertures 21 which are indicated as 22 are disposed to register with corresponding apertures 23 in legs I2. Two additional apertures respectively 24 and 25 are provided in the face of grill and guard portion I0 respectively to receive a light emitting diode and a test button. Near its outer periphery grill and guard portion I0 is provided with a plurality of rearwardly extending projecting members 25 to provide apertures 26 on each of the four sides of the device to facilitate passage of gas into the interior of the device, particularly the gas of the ambient atmosphere, which if a fire is present may be relatively hot and may contain smoke. By providing members 25 in the form of pin-like members as shown. a simple two-part mold devoid of cams may be utilized to economically mold grill and guard portion I0 of any suitable plastic (synthetic polymer resinous) material such as a polycarbonate. polypropylene. ABS or the like. Likewise, portions II, 19 and 20 may also be made with two-part molds, without cams. of the same plastic material.

Speaker bracket portion 16 is provided with an annular curved portion 30 which extends outwardly from loudspeaker 13 on all sides of loudspeaker l3 and pro vides a born for the loudspeaker. Loudspeaker I3 is re ccived in an aperture 31 in the center of horn portion 30 and is retained in place by a threaded member such as screw 32 which may extend through printed circuit board 16 and threadedly engage bracket 33 extending from cup 15.

Base portion 19, printed circuit board 16 and speaker bracket portion II may be secured together by threaded members such as screws 34 extending upwardly through holes 35 provided in base portion I9 and in bosses 36 extending upwardly from base portion 19 which space the lower surface of circuit board 16 above the upper surface of the interior of base 19 a distance indicated as X. Screws 34 extend through holes in printed circuit board 16 into holes 37 in legs 12 which are preferably threaded by self-tapping action of screws 34.

Two required electrical connections to loudspeaker 13 from printed circuit board I6 are provided respectively by wire 38 and (on the ground side) by contact of screw 32 with bracket 33 which is in electrical contact with cup I5.

Base portion 19 may be provided with a plurality of apertures 40 such as the four apertures 40 shown through which wires may pass from the rear of the device to the interior of the device and thence to means which are provided to connect the wires with various circuits of the printed circuit board. Such means may comprise contact plates 4] having serrated upper surfaces 42 and screws 43 which may extend downwardly through holes 44 in printed circuit board 16 and be threadedly engaged with threaded holes in plates 41 provided at 45. As hereinbefore mentioned the printed circuit board I6 may be supported above base portion I9 by bosses so that the lower surface of printed circuit board I6 is a distance above the upper surface of base 19 (in the interior of the device 19) a distance indicated as X. In order to prevent contact plates 41 from falling out of the device if screws 43 are disengaged therewith. distance X is made just slightly less than the thickness of plates 4] which is indicated as Y. Recesses 46 are provided in base I9 to receive plates 4| in order to provide clearance for wire ends between the bottom surface of plate 16 and upper surfaces 42 of plates 4|. The wire ends need not be bent or twisted. They are clamped between plate 16 and surfaces 42 by operation of screws 43. Recesses 47 are provided in bosses 48 which are parts of portion I9 to receive the ends of screws 43 as shown.

Grill and guard portion 10. as previously mentioned, is resiliently deformable and may be provided with downwardly and inwardly projecting portions 50 which may interlock with outwardly projecting portions 5| (which project outwardly from the upper ends of legs 12) to attach grill and guard portion I0 to speaker bracket portion I]. Grill and guard portion I0 is then removable from speaker bracket portion 1] by withdrawing grill and guard portion 10 outward to thereby provide resilient deformation thereof as indicated at I0 and concurrent resilient deformation of downwardly and inwardly projecting portions 50 as indicated at 50'. whereby the interlocking of portions 50 and 5] is overcome so that portion I0 may be removed. To prevent unauthorized removal of portion 10 when the device is located in a relatively public place such as a motel room. a threaded member such as screw 52 may be inserted through each of holes 22 (which as before mentioned are in registry with holes 23 in legs I2) and thence into each of holes 23 where each may preferably be threadedly engaged by self-tapping action of the screw with respect to the interior surfaces of holes 23. When threaded members such as screws 52 are installed, tampering by removal of portion I0 is prevented by persons who are not equipped with screw drivers. Such tamper prevention may be facilitated by providing threaded members 52 as screws which have heads which cannot be engaged with commonly available screw drivers.

A plurality of members 53, two. as shown. being preferable may extend laterally outwardly from portion 30 of speaker bracket portion 11 to engage one side of longitudinally extended battery and resiliently deformable pin-like members 54 may extend upwardly from base 19 to engage a substantially opposite side portion of longitudinally extended battery 55. Two of members 54 may be provided as shown or a greater number may be provided. Battery 55 may be substantially cylindrical as shown or may have any other desired shape. Members 56 may be provided extending upwardly from base portion 19 and may be provided with surfaces 57 to support battery 55 near its ends and may also be provided with surfaces 58 to restrict longi tudinal movement of battery 55. Battery 55 is shown in full lines in FIG. 6 but is shown in dashed lines in FIG. 2 in order to avoid obscuring the view which may be seen in the absence of the battery. Battery 55 is retained in place by the combined action of members 53 and 54 and surfaces 57 and S8 of members 56. Battery 55 is removable by withdrawing it laterally as indicated in dashed lines at 55 and thereby resiliently deforming members 54 as shown in dashed lines at 54 to permit the battery to be withdrawn. In like manner a battery may be installed by pushing it into place with concurrent resilient deformation of members 54.

When the device is drawing on a battery for its power source, its operation may be tested to insure that the battery is supplying adequate power and the rest of the device is working properly by depressing depressible member 60 which may constitute a test button and may extend outwardly through hole 24 in grill and guard portion 10. To slidably support depressible member 60, two members 61 are provided extending laterally from portion 30 of portion 11. Member 61 may provide a portion of a cylindrical bore 62 which may be some what open on one side as indicated at 63. Member 60 may be provided with an outwardly extending portion 64 which may have an annular form as shown and which restricts upward movement of member 60 and also serves as a retainer which is engaged by the upper end of spring 65 which acts against printed circuit board 16 as shown and biases member 60 upwardly. Attached to printed circuit board 16, as previously mentioned, is provided switch 18 which is disposed to be operated by downward movement of member 60 in order to make the necessary connection to cause the battery to operate a loudspeaker 13 in order to test operation of the device. Member 60 may be removed by withdrawing it outwardly as indicated at 60' to provide resilient deformation outwardly of member 61 as shown at 61' and it may be installed similarly simply by forcing it laterally between members 61 to cause them to move into positions shown at 61'.

In the event the device is supplied with I volt line current for its operation a light emitting diode 65 which remains lighted at all times that the device is supplied with power may be mounted in a hole provided in extending portion 66 of member 11 and may extend upwardly through hole 23in grill and guard portion 10. It only a battery is used, light emitting diode 65 is preferably omitted in order to avoid the drain on a battery which is imposed by the diode.

An oscillator to drive loudspeaker 13 may be mounted on the printed circuit board in the usual manner or may be incorporated within cup as indicated at 27 and may comprise a buzzer or oscillating relay. Diaphragm 14in an alternative embodiment might suitably be operated directly by the clapper of a buzzer rather than being driven by a voice coil.

Rear bracket portion may be attached to a wall by screws not shown extending through two or more of holes 70 or two or more of holes 71, holes 70 and 71 being provided in portion 24 for this purpose as well as for other purposes Rear bracket portion 20 is provided with a plurality of outwardly extending resiliently deformable portions 73 which correspond in number to the number of walls 74 which are rearwardly extending from portion 19 and which provide recess 75 in the rear of portion 19. Said portions 73 and walls 74 are four in number (see FIG. 5) in the embodiment shown but may be 3, S or 6 or any other number. Wall 74 is provided with a groove or recess 76 as shown in FIGS. 6 and 4 which need not extend entirely to the end of the wait as indicated in FIGS. 3 and 4. Each of said members or portions 73 may comprise an inwardly extending portion 77 and an outwardly extending portion 78 as indicated in FIG. 6 and shown most clearly in FIG. 9. When portion 19 is attached to portion 20 as shown in FIG. 5, the ends of portions 78 are received in said recesses 74 and said recesses 74 may be described as extending laterally with respect to each of said resiliently deformable outwardly extending members 73.

Base portion 19 may be removed from rear bracket portion 20 by rotating base portion 19 with respect to rear bracket portion 20 so that members 73 are resiliently deformed to a certain extent the relative posi tions of portions 19 and 21) during such rotation being successively indicated by dashed lines 73' and 73".

Alternatively. portion 19 may be removed from por tion 20 by withdrawing it directly outward to provide resilient deformation of extending member 73 as shown in FIG. 9. The position of portion 20 with respect to portion 19 is indicated in full lines at 20, the end of portion 78 being received in recess 76, and the position of portion 20 with respect to portion 19 as portion 19 is withdrawn and members 73 are resiliently deformed is indicated in dashed lines at 20'. 77' and 78'.

It is usually desirable to install base portion 19 on rear bracket portion 20 by twisting portion 19 with respect to portion 20 as indicated in FIG. 5 by considering the steps described above in connection with FIG. 5 as being reversed in the order in which they are carried out. Nonetheless portion 19 may be installed in portion 20 simply by forcing portion 19 directly downward onto portion 20 as indicated in FIG. 9 where the position of portion 20 with respect to portion 19 prior to such installation is indicated in full lines at 20", the position of the portions of member 73 being indicated in full lines at 77" and 78". When portion 19 is pushed toward portion 20 and just before portion 78 snaps into place in recess 76 to provide the orientation indicated in full lines at 77 and 78, the portions have the positions shown in dashed lines at 77" and 78".

As indicated in FIG. 6, portion 20 instead of being fastened directly to a wall may be attached as shown to a standard electrical outlet box 80 which may be recessed in a wall in conventional manner and transformer 81 received in box 80 may be attached to portion 20 by screws 82 self-tapped into holes 70.

Line current such as I 10v. AC may be supplied from a source. not shown for simplicity, to transformer 81 through wires 83 and power at any suitable voltage may be supplied from transformer 81 to printed circuit board 16 through wires extending from transformer 81 to contact plates 41 and screws 43, said wires being not shown for simplicity. Holes 84 may be provided in base portion 19 so that it may be attached directly to an outlet box 80 by screws 85 which may extend through holes 71 in portion 20 and be tapped into holes 86 in the cars of outlet box 80. In a modification of the embodiment shown in FIG. 6, portion 20 may be attached by screws extending through one pair of opposite holes 71 into holes 86 of an outlet box 80 and portion 19 may be oriented with respect to portion 20 so that holes 84 register with the other pair of holes 71 in portion 20. Either portion 19 or portion 20 may be attached to an outlet box oriented in any position, whether vertical or horizontal and on either a wall or ceiling. Screws may then be extended through holes 84 and self-tapped into said other pair of holes 71 so that an unauthorized person cannot then remove portion 19 from portion 20 in the manner discussed in connection with FIG. 5, or for that matter in the manner discussed in connection with FIG. 9. thus preventing an operation which could be considered tampering if carried out by such unauthorized person.

There is thus provided a loudspeaker enclosure which is believed to be unique in comprising a superior combination of superior features as hereinabove described.

it will be apparent to those skilled in the art that equivalents may be utilized.

Accordingly. the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. and acordingly. reference should be made to the appended claims rather than to the foregoing specification as indicating the scope of the invention.

it is claimed:

1. A combination loudspeaker, sensor and printed circuit board enclosure device comprising the combination of:

a resiliently deformable grill and guard portion,

a speaker bracket portion having leg portions.

a loudspeaker comprising a diaphragm and a cup.

a printed circuit board.

an ionization sensor.

a base portion.

a rear bracket portion removably attached to said base portion.

said base portion connected together with said printed circuit board and said speaker bracket portion by threaded members extending from said base portion through holes in said printed circuit board into said leg portions of said speaker bracket portion,

said loudspeaker connected to said printed circuit board by a wire and also connected to said printed circuit board and retained in seated relation to said speaker portion by a threaded member extending from said printed circuit board to a portion of said loudspeaker.

said speaker bracket portion provided with an annularly curved portion extending outwardly from said loudspeaker and providing a horn for said loudspeaker. said sensor connected to said printed circuit board. said base portion provided with a plurality of apertures for receiving wires from the rear of said base portion to connect to said printed circuit board.

said base portion provided with a plurality of means near each of said apertures to connect wires to said printed circuit board.

said grill and guard portion having apertures in front of the loudspeaker and providing a plurality of apertures on each side of the device to receive gas into the device.

said grill and guard portion attached to said speaker bracket portion by projecting interlocking portions and removable from said speaker bracket portion by resilient deformation of said grill and guard portion and said projecting interlocking portions.

2. The device of claim 1 wherein:

said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable members. and

said base portion has a plurality of rearwardly ex tending walls equal in number to the number of said resiliently deformable members extending out wardly from said rear bracket portion. and

each of said walls is provided with a recess in which is received one of said resiliently deformable mem bers extending outwardly from said rear bracket portion. and

each of said recesses is extended laterally with respect to each of said resiliently deformable meni 8 bers extending outwardly from said rear bracket portion which is received therein.

whereby said base portion may be removed from said rear bracket portion by rotating said base portion with respect to said rear bracket portion and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.

3. The device of claim 1 wherein:

said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable members. and

said base portion has a plurality of rearwardly extending walls equal in number to the number of said resiliently deformable members extending outwardly from said rear bracket portion. and

each of said walls is provided with a recess in which is received one ofsaid resiliently deformable mem bers extending outwardly from said rear bracket portion. and

each of said recesses is extended laterally with respect to each of said resiliently deformable members extending outwardly from said rear bracket portion which is received therein.

whereby said base portion may be removed from said rear bracket portion by withdrawing said base portion away from said rear bracket and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.

4. The device of claim 1 wherein means are provided to receive a longitudinally extended battery in said device. said means comprising the combination of:

a plurality of extending members extending from one side of said speaker bracket portion to abut a side of said battery,

two portions extending upwardly from said base portion to support said battery near each of its ends and to restrict its longitudinal movement. and

a plurality of resiliently deformable members extending upwardly from said base portion to contact a side of said battery.

said battery being removable by withdrawing it laterally and resiliently deforming said resiliently deformable members which extend from said base portion.

5. The device of claim 4 wherein:

said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable members. and

said base portion has a plurality of rearwardly ex tending walls equal in number to the number of said resiliently deformable members extending outwardly from said rear bracket portion. and

each of said walls is provided with a recess in which is received one of said resiliently deformable members extending outwardly from said rear bracket portion. and

each of said recesses is extended laterally with respect to each of said resiliently deformable members extending outwardly from said rear bracket portion which is received therein.

whereby said base portion may be removed from said rear bracket portion by rotating said base portion with respect to said rear bracket portion and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.

6. The device of claim 4 wherein:

said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable members and said base portion has a plurality of rearwardly extending walls equal in number to the number of said resiliently deformable members extending outwardly from said rear bracket portion, and

each of said walls is provided with a recess in which is received one of said resiliently deformable members extending outwardly from said rear bracket portion and each of said recesses is extended laterally with respect to each of said resiliently deformable members extending outwardly from said rear bracket portion which is received therein,

whereby said base portion may be removed from said rear bracket portion by withdrawing said base portion away from said rear bracket and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.

7. The device of claim 1 wherein each of said means to connect wires to said printed circuit board comprises a contact plate of conductive material having a serrated upper surface, a recess is provided in said base portion to receive each of said contact plates, said printed circuit board is supported above said base portion to pro vide an aperture to receive the end ofa wire above each contact plate. said aperture is of less height than the thickness of each contact plate so that said contact plate cannot pass outwardly therethrough. and each of said contact plates is provided with a threaded hole to receive a screw extending from said printed circuit board to clamp an end of a wire between the serrated surface of each of said contact plates and said printed circuit board without bending said end around said screw.

8. In the device of claim I, said grill and guard portion having a plurality of rearwardly extending projecting members to provide said apertures on each side of the device to receive gas into the device 9. The device of claim 1 wherein at least two of said apertures in said grill and guard portion which provide a grill in front of the loudspeaker are disposed above two of said leg portions of said speaker bracket portion and said two leg portions are provided with means to receive in threaded engagement therewith threaded members which extend through said two apertures in said grill and guard portion to prevent removal of said grill and guard portion without first unscrewing said threaded members,

10. in the device of claim 1:

said grill and guard member having an aperture to receive a rearwardly slidably depressible member ex tending lrontwardly through said aperture.

said speaker bracket portion having two laterally ex tending resiliently deformable portions said depressible member received rearwardly slid-ably between said two laterally extending deformable portions,

a spring operating between said printed circuit board and said depressible member to bias said depressible member forwardly.

a switch attached to said printed circuit board which is contacted and operated by said depressible member when said depressible member is depressed rearwardly.

characterized by said depressible member being removable by laterally withdrawing said depressible member from said speaker bracket member and thereby resiliently deforming said two laterally ex tending resiliently deformable portions and installable by laterally introducing said depressible member between said laterally extending resiliently deformable portions and thereby resiliently deforming them.

11. In the device of claim 1:

said rear bracket portion provided with two pairs of holes to receive screws to attach it to an electrical outlet box.

said base portion provided with holes to receive screws to attach it to an electrical outlet box in both absence and presence of said rear bracket portion.

said holes in said rear bracket portion disposed to provide both for attachment to an electrical outlet box using one pair of holes and to receive threaded members extending through said holes in said base member and thence through said other pair of holes in said rear bracket member to prevent rotation of said base member with respect to said rear bracket member without first unscrewing said threaded members. 

1. A combination loudspeaker, sensor and printed circuit board enclosure device comprising the combination of: a resiliently deformable grill and guard portion, a speaker bracket portion having leg portions, a loudspeaker comprising a diaphragm and a cup, a printed circuit board, an ionization sensor, a base portion, a rear bracket portion removably attached to said base portion, said base portion connected together with said printed circuit board and said speaker bracket portion by threaded members extending from said base portion through holes in said printed circuit board into said leg portions of said speaker bracket portion, said loudspeaker connected to said printed circuit board by a wire and also connected to said printed circuit board and retained in seated relation to said speaker portion by a threaded member extending from said printed circuit board to a portion of said loudspeaker, said speaker bracket portion provided with an annularly curved portion extending outwardly from said loudspeaker and providing a horn for said loudspeaker, said sensor connected to said printed circuit board, said base portion provided with a plurality of apertures for receiving wires from the rear of said base portion to connect to said printed circuit board, said base portion provided with a plurality of means near each of said apertures to connect wires to said printed circuit board, said grill and guard portion having apertures in front of the loudspeaker and providing a plurality of apertures on each side of the device to receive gas into the device, said grill and guard portion attached to said speaker bracket portion by projecting interlocking portions and removable from said speaker bracket portion by resilient deformation of said grill and guard portion and said projecting interlocking portions.
 2. The device of claim 1 wherein: said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable members, and said base portion has a plurality of rearwardly extending walls equal in number to the number of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said walls is provided with a recess in which is received one of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said recesses is extended laterally with respect to each of said resiliently deformable members extending outwardly from said rear bracket portion which is received therein, whereby said base portion may be removed from said rear bracket portion by rotating said base portion with respect to said rear bracket portion and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.
 3. The device of claim 1 wherein: said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable memberS, and said base portion has a plurality of rearwardly extending walls equal in number to the number of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said walls is provided with a recess in which is received one of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said recesses is extended laterally with respect to each of said resiliently deformable members extending outwardly from said rear bracket portion which is received therein, whereby said base portion may be removed from said rear bracket portion by withdrawing said base portion away from said rear bracket and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.
 4. The device of claim 1 wherein means are provided to receive a longitudinally extended battery in said device, said means comprising the combination of: a plurality of extending members extending from one side of said speaker bracket portion to abut a side of said battery, two portions extending upwardly from said base portion to support said battery near each of its ends and to restrict its longitudinal movement, and a plurality of resiliently deformable members extending upwardly from said base portion to contact a side of said battery, said battery being removable by withdrawing it laterally and resiliently deforming said resiliently deformable members which extend from said base portion.
 5. The device of claim 4 wherein: said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable members, and said base portion has a plurality of rearwardly extending walls equal in number to the number of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said walls is provided with a recess in which is received one of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said recesses is extended laterally with respect to each of said resiliently deformable members extending outwardly from said rear bracket portion which is received therein, whereby said base portion may be removed from said rear bracket portion by rotating said base portion with respect to said rear bracket portion and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.
 6. The device of claim 4 wherein: said rear bracket portion is provided with a plurality of outwardly extending resiliently deformable members, and said base portion has a plurality of rearwardly extending walls equal in number to the number of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said walls is provided with a recess in which is received one of said resiliently deformable members extending outwardly from said rear bracket portion, and each of said recesses is extended laterally with respect to each of said resiliently deformable members extending outwardly from said rear bracket portion which is received therein, whereby said base portion may be removed from said rear bracket portion by withdrawing said base portion away from said rear bracket and thereby resiliently deforming said resiliently deformable members with which said rear bracket portion is provided.
 7. The device of claim 1 wherein each of said means to connect wires to said printed circuit board comprises a contact plate of conductive material having a serrated upper surface, a recess is provided in said base portion to receive each of said contact plates, said printed circuit board is supported above said base portion to provide an aperture to receive the end of wire above each contact plate, said aperture is of less height than the thickness of each contact plate so that no one of said contact plates can pass outwardly therethrough, and each Of said contact plates is provided with a threaded hole to receive a screw extending from said printed circuit board to clamp an end of a wire between the serrated surface of each of said contact plates and said printed circuit board without bending said end around said screw.
 8. In the device of claim 1, said grill and guard portion having a plurality of rearwardly extending projecting members to provide said apertures on each side of the device to receive gas into the device.
 9. The device of claim 1 wherein at least two of said apertures in said grill and guard portion which provide a grill in front of the loudspeaker are disposed above two of said leg portions of said speaker bracket portion and said two leg portions are provided with means to receive in threaded engagement therewith threaded members which extend through said two apertures in said grill and guard portion to prevent removal of said grill and guard portion without first unscrewing said threaded members.
 10. In the device of claim 1: said grill and guard member having an aperture to receive a rearwardly slidably depressible member extending frontwardly through said aperture, said speaker bracket portion having two laterally extending resiliently deformable portions, said depressible member received rearwardly slidably between said two laterally extending deformable portions, a spring operating between said printed circuit board and said depressible member to bias said depressible member forwardly, a switch attached to said printed circuit board which is contacted and operated by said depressible member when said depressible member is depressed rearwardly, characterized by said depressible member being removable by laterally withdrawing said depressible member from said speaker bracket member and thereby resiliently deforming said two laterally extending resiliently deformable portions and installable by laterally introducing said depressible member between said laterally extending resiliently deformable portions and thereby resiliently deforming them.
 11. In the device of claim 1: said rear bracket portion provided with two pairs of holes to receive screws to attach it to an electrical outlet box, said base portion provided with holes to receive screws to attach it to an electrical outlet box in both absence and presence of said rear bracket portion, said holes in said rear bracket portion disposed to provide both for attachment to an electrical outlet box using one pair of holes and to receive threaded members extending through said holes in said base member and thence through said other pair of holes in said rear bracket member to prevent rotation of said base member with respect to said rear bracket member without first unscrewing said threaded members. 